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PubMed1987

Differentiation of maximal from submaximal static elbow flexor efforts by measurement variability.

Thirty-one young women subjects performed four maximal and four submaximal elbow flexion efforts. The strength of each effort was measured using make tests and a hand-held dynamometer. The variability of repeated maximal and submaximal tests was determined by calculating CVs for each subject. Every subject's CV was greater during submaximal than during maximal trials. Furthermore, the mean CV was significantly greater during submaximal trials than during maximal trials. No subject demonstrated a CV greater than 7.5 per cent for maximal trials, but most had CVs greater than 7.5 per cent for submaximal trials. The results suggest that for the subjects tested CVs greater than 7.5 per cent were consistent with feigned weakness. Coefficients of variation above 7.5 per cent were not, however, limited to subjects feigning weakness. Further investigations of strength variability are needed under different conditions before confident judgements can be made about patient performance.

Adult↗
PubMed1997

Normalizing strength for body size differences in older adults.

The purpose of this study was to compare the normalization methods of ratio standards, allometry, and ANCOVA with knee extensor strength of older adults. The apparently healthy older volunteers were 71 men (mean +/- SD; age, 71 +/- 4 yr; body mass, 81 +/- 10 kg; height, 174 +/- 7 cm) and 77 women (71 +/- 4 yr, 65 +/- 8 kg, 160 +/- 5 cm. respectively). Strength was defined as peak torque (N.m-1) and measured with a Cybex II isokinetic dynamometer. Body composition was estimated with dual energy x-ray absorptiometry. With allometry, the body mass exponent (0.74) was not statistically different from theory (0.67). Body mass adjusted strengths were 34.7% (allometry), 32.0% (ANCOVA), and 29.4% (ratio standards) greater in older men than women. Allometry revealed that the bone-free lean tissue mass exponent was not different from ratio standard exponent of 1.0. After adjustment by bone-free lean tissue mass, strength in men remained 16.0% (allometry and ratio standards) higher than in women, but, strength differences between genders were eliminated with ANCOVA. The methods used to normalize strength yielded similar results with body mass but conflicting results with bone-free lean tissue mass.

Aged↗
PubMed2004

Groin injuries in professional rugby league players: a prospective study.

Altogether, 100 uninjured professional rugby league players were evaluated over a 2-year period. Their height, body mass, sum of skinfolds, girths and bone diameters were recorded. A Cybex 340 isokinetic dynamometer was used to determine peak torque, work, power, endurance ratios and peak torque ratios of the hip abductors and adductors (5 repetitions at 0.52 and 2.08 rad. s(- 1); 20 repetitions at 3.66 rad. s(- 1)) and knee flexors and extensors (4 repetitions at 1.04 and 3.14 rad. s(- 1); 30 repetitions at 5.22 rad. s(- 1)). Hip abduction and adduction were also assessed with the hip in external rotation. Discriminant function analysis was conducted on all predictor variables to develop a multivariate predictive model capable of classifying players with a high degree of accuracy into groups with and without a groin injury. The model consisted of eight variables and correctly classified 91.7% of the non-injured players and 90.5% of the injured players. The correct classification for the model as a whole was 91.4%. The aetiological factors identified as being related to injury of the groin musculotendinous unit included abduction and adduction-with-rotation peak torque, angle of adduction and abduction-with-rotation peak torque, strength ratio of hip muscle groups, bilateral difference in extension peak torque, femur diameter and body mass.

Adult↗
PubMed1996

Peak torque, average power, and hamstrings/quadriceps ratios in nondisabled adults and adults with mental retardation.

OBJECTIVE: To compare isokinetic hamstring and quadriceps peak torque (Nm), average power (watts), and corresponding hamstring/quadriceps (HQ) ratios (as percentages) of adult men with Down syndrome(DS), with mental retardation without Down syndrome (NDS), and nondisabled sedentary controls (SC). DESIGN: Repeated measures analysis of variance. SETTING: Subjects were tested at a university exercise science laboratory. SUBJECTS: Volunteer sample of 35 subjects: SC(n=13), DS(n=9), and NDS (n=13). INTERVENTION: Subjects performed isokinetic strength tests at 60 degrees /sec and 90 degrees/sec using gravity effected torque procedures. Subjects with DS and NDS performed the test on two separate days with best results selected for statistical comparisons. Sedentary controls performed the test once. MAIN OUTCOME MEASURES: Isokinetic hamstring and quadriceps peak torque and average power, and corresponding HQ ratios on a Cybex 340 isokinetic dynamometer. RESULTS: In all isokinetic parameters measured, sedentary controls demonstrated significantly higher scores than subjects with DS and NDS. There was no significant difference between subjects with DS and NDS, although mean peak torque and average power scores were greater in subjects with NDS. Finally, there were no significant differences in peak torque and average power HQ ratios across groups (p> .01), although group mean peak torque HQ ratios were greatest for sedentary controls (range=61% to 63%) and approximated accepted HQ ratio norms, and lowest for subjects with DS(range=40% to 46%). CONCLUSIONS: Individuals with mental retardation are in need of progressive resistance exercise programs to improve hamstring and quadriceps strength and normalize HQ strength and power ratios.

Adult↗
PubMed1991

Relationships among strength, endurance, weight and body fat during three phases of the menstrual cycle.

The purpose of this study was to investigate the relationships among body weight, body fat, and dynamic strength and muscular endurance during different phases of the menstrual cycle. Twenty-one female subjects, ages 18-36, with normal menstrual cycles and no dysfunction were tested for strength and endurance of the knee flexors and extensors on a Cybex II isokinetic dynamometer. Body weight and percent body fat were also assessed. Each subject was tested at three speeds (60 degrees, 180 degrees, and 240 degrees/sec) during three phases of the menstrual cycle: mensus (within 24 hours of onset); ovulation (13-14 days from onset); and luteal (10 days from ovulation). The data were analyzed descriptively and by Pearson Product-Moment Correlations with each phase of the cycle and between cycle phases. Results indicated high correlations among most strength measures at the three test speeds for each phase during the cycle and between the cycle phases. Overall, the different phases of the menstrual cycle had little or no effect upon the relationships among body weight, percent body fat, knee extension and flexion strength or endurance.

Adipose Tissue↗
PubMed1999

Normative values of agonist-antagonist shoulder strength ratios of adults aged 20 to 78 years.

OBJECTIVE: To determine normative values for isometric flexion/extension, abduction/adduction, and external/internal rotation strength ratios about the shoulder and to determine if these ratios are affected by age or gender. STUDY DESIGN: A cross-sectional study of 120 healthy volunteers (60 men, 60 women) aged 20 to 78 years. SETTING: Orthopedic research laboratory. METHODS: Flexion and extension strengths were measured isometrically using a Cybex II dynamometer at arm flexion angles of 30 degrees, 60 degrees, and 90 degrees. Abduction and adduction strengths were measured at 30 degrees, 60 degrees, and 90 degrees abduction. Internal and external rotation strengths were measured (1) with the arm abducted 15 degrees and neutral external/internal rotation and (2) with the arm abducted 90 degrees and externally rotated 30 degrees above the transverse plane. OUTCOME MEASURES: Isometric strength ratios for flexion/extension, abduction/adduction, and external/internal rotation. RESULTS: No statistically significant differences in agonist/antagonist strength ratios were found between dominant and nondominant sides or between genders. Age was associated with changes in strength ratios for measurements taken with the arm flexed or abducted 90 degrees. Posture was found to affect strength ratios. CONCLUSIONS: These data can serve as a normative reference for clinical use.

Adult↗
PubMed1994

Early and intensive physiotherapy accelerates recovery postarthroscopic meniscectomy: results of a randomized controlled study.

The efficacy of an early, intensive, supervised rehabilitation program to accelerate knee strength recovery in the first 3 weeks postmeniscectomy by arthroscopy was evaluated using a randomized controlled trial design. The maximal voluntary isokinetic strength of 31 men, randomly allocated to either a treatment (EXP) or a control (CTL) group, was measured twice by a blind rater: preoperatively (pretest) and 3 weeks postsurgery (posttest), using a computer-controlled Kin-Com dynamometer (Chattecx Corporation, Chattanooga, TN). Strength deficits of the operated leg at the pretest and posttest were established in percent of the values obtained for the sound leg at the pretest. In the interval between the surgery and the posttest, the patients of the EXP group (n = 15) received nine supervised treatments combined to home exercises whereas patients of the control group (n = 16) had no specific physiotherapy treatment but were given instructions in postsurgical management and prescribed exercises by the orthopedic surgeons. Patients of the EXP group had better knee extensor strength recovery than patients of the CTL group (ANCOVA, p < 0.001). The size of the strength difference (3 weeks postsurgery) between EXP and CTL subgroups (n = 8) matched according to preoperative deficits was as large as 26% and the residual deficits of the untreated patients were two to three times larger than those of the treated patients. The results of this study highlight the importance of instituting an early intensive and supervised rehabilitation program, especially for workers returning to a strenuous job requiring good knee extensor muscle function.

Activities of Daily Living↗
PubMed2005

Shoulder function in patients with frozen shoulder before and after 4-week rehabilitation.

UNLABELLED: This study evaluated changes in shoulder function in patients with frozen shoulder after 4-week rehabilitation combining exercise with electrical therapy and massage. MATERIAL AND METHODS: Ten patients with frozen shoulder (mean +/- standard error (SE) age 50.2+/-4.6 years) and 10 control subjects (49.8+/-4.6 years) participated in the study. Standard goniometric measurements were used to assess shoulder flexion, extension, abduction, adduction, internal and external rotation active range of motion. Isometric maximal force of the shoulder flexors, abductors, adductors, internal and external rotators was measured by hand-held dynamometer. Shoulder muscle isometric endurance was characterized by net impulse assessed during weight (30% of maximal force) holding in hand till exhaustion. Shoulder pain was assessed by visual analogue scale. RESULTS: Before rehabilitation, patients with frozen shoulder had less (p<0.05) active range of motion and shoulder muscle maximal force for all measured directions, and less (p<0.05) net impulse during shoulder muscle isometric endurance test for involved extremity compared to controls. In patients with frozen shoulder, shoulder flexion, abduction, adduction and adduction active range of motion, maximal force of shoulder muscles in all measured force directions and net impulse during shoulder muscle isometric endurance test for involved extremity increased (p<0.05) after rehabilitation. No significant changes in shoulder internal and external rotation active range of motion for involved extremity in patients with frozen shoulder were observed with rehabilitation. CONCLUSION: A 4-week rehabilitation program improved shoulder flexion, extension, abduction and adduction active range of motion in patients with frozen shoulder coupled with non-significant changes in external and internal rotation range of motion. A significant increase in shoulder muscle isometric strength and endurance and decrease in shoulder pain in patients with frozen shoulder was observed after treatment.

Adolescent↗
PubMed2001

Isokinetic strength related to jumping but not kicking performance of Australian footballers.

The relationships between lower limb strength and two Australian football (AF) skills were assessed for 19 sub-elite AF players. Knee extension (KE) and knee flexion (KF) strength were assessed using a Biodex isokinetic dynamometer at angular velocities of 60, 240 and 360 degrees/sec. The two AF skills evaluated were running vertical jump (VJ) and kicking performance (KP). VJ performance was defined as the maximal jump height measured with a Yardstick device. KP was gauged through video analysis, as the post-contact resultant ball velocity (BV) during maximal effort drop punt kicking. Strength was measured as the isokinetic peak torque (PT value. No significant correlations were detected between the isokinetic knee strength values and maximal kicking velocity. Low to moderate significant correlations (r = 0.55 - 0.69, p < 0.05) were detected between the isokinetic measures and VJ height. It may be inferred that additional strengthening of the knee musculature may enhance running VJ performance, but not necessarily kicking velocity for this group of sub-elite AF players.

Adult↗
PubMed1996

Isokinetic evaluation of calf muscle performance after Achilles rupture repair.

The purposes of this study was 1) to assess the plantar flexion and dorsiflexion peak torques (PT) of the ankles at 30, 90 and 240.. s-1 in 101 patients (86 men, 15 women) who had been operated on for unilateral, complete closed Achilles tendon (AT) rupture at Oulu University Hospital, Oulu, Finland, in the period 1987-1992, 2) to determine whether comparison between the legs shows any impairment, 3) to study whether the weakness is speed-dependent, 4) to determine at what angular displacement of the ankle the weakness is manifested, 5) to study how the results correlate with age, type of operation and follow-up time. The Lido Multi-joint II dynamometer was used for the measurements. There was no significant dorsiflexion weakness detectable upon comparison between the legs, but the mean relative peak torque deficits in the injured limb were 8.4, 9.0 and 3.0% at 30, 90 and 240.. s-1 respectively for the men and 15.0, 16.6 and 6.4% for the women. The mean percentage torque differences were significantly greater in the women at all the test speeds (p < 0.05). The difference in PT was significantly greater at the two low test speeds (30 and 90.. s-1) than at the high speed (240.. s-1, p < 0.001). The weakness was manifested at an angular displacement of 80-120 degrees, where the average peak work (PW) difference between the two legs was significant in both sexes (p < 0.05). The patient's age (21-63), the type of operation (Lindholm or Silfverskiöld technique) and the follow-up time (0.7-6.7 years) did not significantly affect the results. In conclusion, and AT rupture implied an average 3.0 to 16.6% impairment in isokinetic plantar flexion muscle strength. The impairment was greater in the women, was manifested at an angular displacement of 80-120 degrees, and was greater at low test speeds. Age, type of operation and follow-up time did not account for the PT differences between the patients.

Achilles Tendon↗
PubMed2004

Adequacy of simple measures for characterizing impairment in upper limb strength following stroke.

Simple measures are sometimes used to characterize weakness in the upper limb after stroke, but their reliability and validity remain uncertain. Here, we examined the adequacy of three measures relative to dynamometer measurements of 26 patients (15 women and 11 men, M age=70.1 +/- 11.7 yr.) with acute stroke. The strength of the involved upper limb was characterized using the National Institutes of Health Stroke Scale: Motor Functions-Arm (drift test), the Stroke Impact Scale: Arm and Hand (self-report), and objective dynamometry. Correlations between the simple measures and dynamometry were significant (r(s)=.70-.87). However, none of the 8 patients who achieved the best NIH scale-Arm score (0: no drift) self-reported having "a lot of strength." Dynamometry indicated that the strength of these patients was less than 50% of that expected according to published norms. The three simple measures examined had convergent validity, but drift, as scored on the NIH scale, was not sensitive to mild or moderate weakness of the upper limb after stroke.

Acute Disease↗
PubMed1998

Quadriceps strength and timed motor performances in myotonic dystrophy, Charcot-Marie-Tooth disease, and healthy subjects.

BACKGROUND AND PURPOSE: The leading hypothesis was that a relation exists between muscular strength and functional abilities. Therefore a study was undertaken to quantify such a relationship in a population of subjects with different muscular strengths. This population consisted of healthy subjects and subjects with slowly progressive neuromuscular disorders. METHODS: The study included 33 patients with myotonic dystrophy, 29 patients with Charcot-Marie-Tooth disease and 20 healthy subjects. Isokinetic and isometric knee torques were measured on an isokinetic dynamometer at various velocities. The following activities were timed: descending and ascending stairs, rising from a chair, rising from supine, walking at natural speed and walking at maximum speed. RESULTS: The population covered a wide range of the variables: whereas the healthy subjects performed best (i.e. had the highest knee torques and performed the activities most quickly), the myotonic dystrophy group included the subjects with the lowest knee torques. The natural logarithms (In) of isokinetic extension torque at the highest velocity (120 degrees/s) and those of the time taken to perform the described activities showed the highest levels of correlation. It was found that after correction for age and weight, 56% (walking at natural speed) to 73% (descending stairs) of the variance in the In of the time taken could be attributed to the variance in the In of the torques. CONCLUSION AND DISCUSSION: A strong relation between quadriceps strength and timed motor performances were demonstrated. The impact of strength reduction on time taken was most obvious in subjects with considerably decreased strength. Therefore, it is feasible to try to influence muscle strength in patients with relevant strength reduction in order to achieve better functional ability.

Adolescent↗
PubMed2005

[Nutritional assessment in patients with cirrhosis: the use of indirect calorimetry].

BACKGROUND: Malnutrition is frequent in cirrhotic patients, and its assessment is difficult. Functional assessment through a dynamometer is a simple method and could minimize these drawbacks. Harris-Benedict prediction formulae estimates the resting energy expenditure but has not been validated for this population. One alternative is the use of indirect calorimetry. AIM: To assess nutritional status in cirrhotic patients and estimates the resting energy expenditure through indirect calorimetry and compares it to Harris-Benedict. PATIENTS AND METHODS: Thirty four adult hepatitis C cirrhotic outpatients were studied, classified by Child-Pugh and model of end-stage liver disease score. The resting energy expenditure was predicted through Harris-Benedict and measured by indirect calorimetry. Nutritional assessment was done through anthropometry, subjective global assessment, hand-grip strength and a 3-day recall. RESULTS: Fifteen (44.2%) were Child-Pug A, 12 (35.3%) B and 7 (20.6%) C, and 33 (97.1%) had model of end-stage liver disease scores less than 20. The resting energy expenditure predicted was higher than the measured (Harris-Benedict 1404.5 +/- 150.3 kcal; indirect calorimetry 1059.9 +/- 309.6 kcal). The prevalence of malnutrition varied between methods (body mass index, muscle arm circumference, subjective global assessment, triceps skinfold thickness and hand-grip strength: 0; 5.9; 17.6; 35.3 and 79.4%, accordingly). Calories and proteins intake were 80% and 85% of recommended amounts and there was inadequate intake of calcium, magnesium, iron and zinc. CONCLUSION: Malnutrition was frequent and hand-grip strength seemed to be the most sensitive method for its diagnosis. Calories and protein intakes were inadequate. Considering that the predicted resting energy expenditure was higher than the measured one and the need to offer higher caloric intake, the use of the predicting equation may replace indirect calorimetry.

Adult↗
PubMed1984

Hand strength and prone extension in right-dominant, 6 to 9 year olds.

A stratified random sample of 153 right-dominant children (6 to 9 years of age) with normal or above intelligence was selected to study the development of hand strength, and the quality and duration of prone extension as a function of age, sex, height, and weight of the child. The Jamar hand dynamometer was used to measure hand strength, and a new scale for rating the quality of prone extension was presented. Both right- and left-hand strength increased monotonically with age, with the right being significantly higher than the left. Duration of prone extension increased monotonically with age, but quality of prone extension did not correlate with age. Sex differences were found only on the variable left-hand strength (males greater than females). Hand strength demonstrated weak correlation with duration of prone extension. Both height and weight exhibited strong positive correlations with hand strength, weaker positive correlations with duration of prone extension, and no correlation with quality of prone extension. The results suggest hand strength can be an index of normal development, and children ages 6 to 9 can attain the prone extension position; however, the meaning of duration greater than 30 seconds needs to be researched further.

Age Factors↗
PubMed1999

Manipulative management of post-Colles' fracture weakness and diminished active range of motion.

OBJECTIVE: To discuss the management of a patient with wrist weakness and a diminution in active range of motion resulting from Colles' fracture. CLINICAL FEATURES: A 58-year-old woman complained of persistent loss of grip strength and mobility in her right wrist. These complaints were from Colles' fracture occurring 19 months before initiation of care. Dynamometer and goniometric testing revealed significant loss of grip strength and range of motion compared with the uninvolved, nondominant wrist. INTERVENTION AND OUTCOME: Specific joint manipulation for improvement in mobility and grip strength of the wrist was performed. The patient's right wrist was evaluated for grip strength and active range of motion over a 3-week period, providing a baseline of function before treatment. After 4 visits of baseline measurements, a series of 4 treatments and 4 reevaluations was performed. The patient exhibited a significant increase in grip strength and active range of motion. CONCLUSION: Appropriate intervention of chiropractic manipulation and examination procedures culminated in a successful resolution of this case. When such cases are recognized, appropriate management may occur conservatively with judicious application of joint manipulation and reevaluation procedures.

Colles' Fracture↗
PubMed2001

Quantifying associated reactions in the paretic arm in stroke and their relationship to spasticity.

OBJECTIVES: (1) To present a measurement protocol for assessing associated reactions (AR) in the paretic arm and (2) to use it to investigate the pattern of AR and its association with spasticity. SETTING: Inpatient rehabilitation unit. DESIGN: Associated reactions in 49 adults with stroke were measured in terms of force generated, electrical muscle activity and wrist movement in the paretic arm using hand dynamometry, surface electromyography and electrogoniometry respectively. Simultaneous recording of the effort used to elicit the associated reaction was made using a second hand dynamometer. The magnitude and persistence of AR was compared with the clinical assessment of spasticity (using the modified Ashworth Scale, MAS). RESULTS: There was poor correlation between peak AR and MAS, suggesting that AR are not confined to patients with severe spasticity. Co-activation of forearm flexors and extensors was evident during the AR. AR fluctuated during a single period of effort in some patients. Only 12 out of 31 patients who maintained uniform effort over the measurement period produced a uniform AR. AR often persisted for some time after effort had ceased. Eight were classified as minimal (median AR 0.23 N), 25 as mild (median AR 2.7 N), 11 as moderate (median AR 6.4 N) and 3 as severe (median AR 11.0 N). AR tended to persist in patients with higher MAS although this result was not statistically significant. CONCLUSION: The magnitude, profile and persistence of AR varied considerably between individuals. Associated reactions were present in people with minimal spasticity. As this technique allows the magnitude of AR to be quantified in relation to effort it has the potential to be a useful outcome measure in clinical trials evaluating the treatments (e.g. physiotherapy) directed at reducing associated reactions.

Activities of Daily Living↗
PubMed2003

The effect of short-term isokinetic training on force and rate of velocity development.

This study determines the effects of short-term isokinetic training on rate of velocity development (RVD) and force. Three groups were pre- and posttested for knee extension RVD and force at 1.04 (slow) and 4.18 rad.s(-1) (fast) on a Kin-Com dynamometer. The slow and fast groups completed 2 days of velocity-specific training, whereas the control group did not train. Four-way analysis of variance results demonstrated significant (p < 0.05) decreases in RVD between pre- and posttests for the slow group at the slow velocity (RVD-1.25 +/- 0.04 degrees vs. 1.08 +/- 0.03 degrees ) and for the fast group at the fast velocity (RVD-14.24 +/- 0.33 degrees vs. 13.59 +/- 0.29 degrees ). Force exhibited no significant differences between testing days for any group. These results demonstrate that short-term isokinetic training results in velocity-specific RVD improvements. These acute RVD improvements may serve to offset strength deficits in power environments on the basis of the mutable relationship between force and velocity.

Adult↗
PubMed1996

Hand grip increases shoulder muscle activity, An EMG analysis with static hand contractions in 9 subjects.

We examined 4 shoulder muscles--the supraspinatus, infraspinatus, the middle portion of the deltoid and the descending part of the trapezius--with electromyography (EMG) in adducted and flexed arm positions, in 9 healthy subjects. The subjects were asked to produce a static handgrip force of 30% and 50% of maximal voluntary contraction (MVC) in 8 different arm positions. In all positions, the subjects held a dynamometer in the hand. The myoelectric activity in the shoulder muscles with only the dynamometer in the hand was compared to the EMG activity when static contractions were added. There was an association between static handgrip and shoulder muscle activity, as revealed by E < G. The EMG activity increased in the supraspinatus muscle in humeral flexion from and above 60 degree in 120 degree abduction. In the infraspinatus muscle, the changes were less; a significant increase, however, was noticed in flexion. In the deltoid muscle there was a tendency towards increased activity in positions lower than 90 degree, in the higher arm positions, the activity decreased. There was no significant alteration regarding the EMG activity of the trapezius. Our findings imply that high static handgrip force, particularly in elevated arm positions, increases the load on some shoulder muscles. The stabilizing muscles (the rotator cuff) were more influenced than the motor muscles by hand activity. Handgrip activity is important to evaluate while assessing shoulder load in manual work an in clinical evaluations of patients with shoulder pain.

Adult↗